General Hex Question

This is probably going to sound like a really stupid question, but I need to ask it anyway.

I want to edit some events and other things, but the thing that is plaguing me right now is understanding how to add to the event without deleting everything else.

So example, I'm working on the intro scene at the Narshe cliff. How do I add another character for the game to create without deleting the next byte of information?

So it might read 3D003D0E3D0F for creating characters followed by 45 for refresh. How do I add another character after 0F without deleting the next byte (45). Is there a way to edit and "insert" instead of removing? But then, won't this mess up the rest of the game?